Unit heater



' Sept. 26, 1944. w. J. HARTWEG UNIT HEATER Filed Oct. 24, 1942 3 Sheets-Sheet 1 ZNVENTOR.

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Patented Sept. 26, 1944 UNITED STATES A NT OFFICE UNIT HEATER Walter J. Hartwig, Wausau, Wis., assignor to D. J. Murray Manufacturing (30., Wausau, Wis., a corporation of Wisconsin Application October 24, 1942, Serial No. 463,187

Claims. (Cl. 257-137) The present invention relates generally to improvementsin the art of heat transfer, and relates more specifically to improvements in the construction and operation of so-called unit heaters and blast coils for normally imparting heat to a stream of air'fiowing in a predetermined direction.

A general object of my present invention is to provide a new and useful unit heater assemblage which is simple in construction and efficient in operation.

Numerous types of unit heaters for ,constantly imparting heat to a stream of air and for delivering the heated air in desired directions, have heretofore been in common use for diverse purposes, and most of, these prior heating units embody a heat transfer coil or grid assembly, a fan or blower for causing the air to flow past the heat transfer assembly, and means for caus-' ing the heated air to flow in a predetermined direction. In the more efiicient forms of these prior unit heaters, the coil assembly is constructed of a series of independent parallel finned radiator sections having their opposite ends detachably associated with heating fluid sup-- ply and discharge headers; and .this grid assemblage is housed within a special outer castion is to provide an improved unit heater comprising relatively few parts adapted to be produced by casting and with minimum machining,

, and wherein the heating fluid conducting conduits-are devoid of joints which might introduce objectionable leakage.

A further specific object of this invention is to provide a durable and highly efficient finned heat transfer radiator having a plurality of finned sections formed integral with common heating fluid supply and discharge headers, and

which can be readily constructed of east ironor the like and at minimum cost with ordinary foundry equipment.

, Still another specific object of the invention is to provide a compact heating unit having relatively few parts which may be readily assembled or dismantled,-and wherein a continuous stream or current of air may be constantly heated and properly directed toward the'zone of utilization.

An additional specific object of the present invention is to provide an attractive unit heater assemblage of the grid type which occupies minimum space considering its capacity, and which may also be readily suspended from above I or mounted from substructure with the blower ing or housing having a louvered or similarly ;controlled outlet opening and an alined air inlet opening provided with a motor driven fan which is in some manner suspended from the heat transfer assemblage. In practically all of the previous finned radiator assemblies it was necessary to cast or to otherwise produce the externally finned radiator sections independently of each other and of the headers, and to thereafter assemble the various parts with leakproof joints, because of the fact that the fins must be disposed closely adjacent to each other in order to obtain maximum efficiency; and in some of the prior finned structures, the relatively frail and thin fins were formed of special relatively rare metal having high heat conductivity and were attached to the more bulky conduit portions of the radiator sections by casting or otherwise. costly to construct and to assemble the prior heat transfer assemblages of this type so as to maintain leak-proof joints, and recent restrictions placed upon the use of certain materials have also precluded the-use thereof for many purposes including the manufacture ,of' unit' heaters. 1 p

The present invention therefore contemplates various improvements in the details of con-,

struction of finned grid type unit heaterassemblages, of simplified construction and adapted to It was therefore difficult and" structure rigidly associated with the radiator and louver assemblies so as to produce'a unitary assemblage.

These and other specific objects and advantages of the present improvement will be apparent from the-following detailed description.

A clear conception of the various features constituting my present invention, and of the mode of constructing, assembling and operating one of the improved unit heaters, may be had by referring to thedrawings accompanying and forming a part of this specification wherein like reference characters designate the 531118101 similar. parts in the several views.

Fig. 1 is a side elevation of one of the improved unit heaters, .completely assembled and adapted for overhead suspension, and ready for operation; 2 is a front view of the same unit heater but with portions broken away to reveal normally concealed structure; e j Fig. '3 is avertical section through the assembledunit heater, showing the motor driven ,fan in elevation; I

Fig. 4 is a rear view of the unit heater as- I semblage 'Fig; 5 is apart sectional front view of one of the finned radiator units comprising several sections and integral headers;

' line 6-6; and

;Fig. 7 is an isometric perspective .view ofthe sections, it is not my desire or intent to unneces- V sarily restrict the scope or utility of the improved features some of which may 'obviously be advantageously applied to other types of heaters such as blast coils and to unit coolers as well as heaters.

Referring to the drawings, -my prese'nt improved unit heater comprises in general-a pairof similar reversely positioned and inter-locking" lieattransfer elements 8' each having a plurality "ofparallel vertically disposed finned conduit sections '9 formed integral with'a common upper heating fluid supply header lo and' with a common lower spent fluid discharge header II; a 'series of horizontal pivotally suspended adjustable warm air flow controla'nd directing louvers I2 'swingably suspended from front side flanges I3 oneof which is formed integral with each of the elements '8;an air impeller or fan I4 located 'rearwardly of the finned conduit sections '9 in horizontal alinement with the louvers I2 and'c'o operating with a rear casing I5 to direct'a-stream of air past the finned heat transfer sections 9;

and 'an electric motor I6 drivingly associated with'the 'fan I4 and being suspendedfrom the casing I5 and the elements 8 by m'eans'ofasupporter bracket" I'I formed integralwi-th the rear casing I15.

Thespecific construction of the individualonepiece elements 8 is clearly shown in Figs."5,6

and-'7, and each of these unitary elements may be readily constructed of any suitable and available metal such as cast iron, and by ordinary foundry methods, by virtue of the fact that the 1 successive parallel finned conduit sectionst of 'each elementt, are separated laterally by wide open spaces as indicated in Fig. "5. Each of the upright radiator sections 9 isprdvided with a plurality of parallel approximately"rectangular fins I8 and with *a relatively wide and narrow internal'heating fluid conducting passage I9 as shown in Figs. 5 and 6; and since the finnedsections 9 are formed integral with the supply-and "discharge headers I0, II 'and thepassages I8 are in open communication with the headers adjoining the ends thereof, no joints or s'eals of any 'kind are required between the radiating sections sand the headers II), II. In order to facilitate supporting of the foundry cores'for the wide Dassages I9, the opposite ends ofthe finned sections 9 may be provided with openings which may subsequently be sealed by *pipe plugs and the opposite ends of each of the hori'zontal headers I0, II are also provided with threadedopenin'gs one of which is normally sealed'by a pipe plug 2I and the other'of which isconnec't'ed eith'ep'to a heating fluid inlet pipe22-orwith-a s'pentfluid outlet pipe 23. Besides the 'front sidefiange I3,

' each heating coil element 9 is also provided with a rear side flange 24 and with a'set of sidebosses 25'for receiving suspension bolts 26, and these bolts may be utilized to suspend the unitfrom 'above. The 'w'arm' air flow control ahd directing louvers I2 are swingably suspended frdmthe'opposite side flanges I3 of the two coil sections in 'front of" the elements 8', by ii'leans'of frictionpiv- "'otsor screws 21, and may thereforebe" adjusted and disposed in any desired angular position.

In order to-"permit two 'of the similar-heat transfer elements 8 to be assembled and interlooked as shown in Figs. 1 to 4 inclusive, the headers III, II of the two heat transfer units are off-set rearwardly and forwardly'so that the corresponding headers of the two elements 8 are disposed-on opposite sides of the common cen- "tral vertical plane passing through all of the fi'n'ned sections 9; and the headers I0, II are provided with contact lugs 28 which extend throughout the lengths thereof and may be dressed to close the gap between the adjacent headers'so as to prevent undesirable escape of warmair therebetween. The upper and lower heavy'fins or local flanges 29, 30 respectively of thesections 9 are also preferably made heavier and longer than the intermediate fins I8 so that when the two elements 8 are assembled, these longer localflanges'ZB;30'wil1 form top and bottom closure walls for the air duct and will also cooperate "with the rear side'flanges 24 to provide' means for'attaching the fan casing I5. The stout upper and lower flanges 29,"3Ilmay also be provided with transve'rselu'gs3I which are adapted to be dressed'so as" to coact with and to properly position'the headers II); II of the complementary heat transfer elementsa; so' that the adjacentfins'l8 and flanges 23, 30"will all be properly "alined' in the final assemblage.

The fan casing =I5 'andthe'fan motor "supporting bracket II'may be'for'med integral'with each-'othen'and this integralasse'mblage may be 'firmly attachedto 'the'rear 'ends of the upper 'andlower fianges"29, 3ll'=and"to"the'rear side flanges 24"by means -'bf rivets or bolts 32, as

shown in Figs. same, thereby'also locking the two radiatorelements '8 in assembled position.

-The suspension bracket I! may be'provided with an insulating pad 33'0r the like, upon which the electric'motcr IB may be mounted in'any'de'sired mannerjand the rotary'fan I4 which'is revolvable in acircul'ar'central opening 34forme-d in the casing I5 in horizontal alinement withthe finned *sections 9, is mounted directly upon the motor a shaft 35.

In order to permit most eifi'cient operationand flexibility in use, it is preferable to have the motor I6 operable at several speeds, and

the supply or inlet pipes 2'2- may be provided with either independent or acommoncontrol valve 'so that either oneor both elements 8 may 'be sup- "plied with heating medium; or the heating fluid may be shut oif entirely.

'When' the several "elements 8, louvers I2 and casing I5 of the improved unit heater have been J properly constructed by ordinary foundry methods, they may be dressed' so as-to properly coact -'with" each other bymer'ely grinding or filing rough'areas-and "by drilling holes for the'reception of the screws 21, 32, whereup'on they may be quickly assembled as illustrated in Figs. 1 to 4 inclusive. "Since the 'two' elements 8 are interchangeably similar, they'inay be'molded and cast 1 from the 'sa'me'patt'ern, and each elementa may "be provided with any desired number of finned "sections 9. Themo't'or driven fan I4 may be of relatively "standard construction, and after the 'motor'IS hasbeen mounted upon the bracket I! with the fan I4"disposed centrally of the circu lar opening 34, and suspension bolts 26 have 1 been applied to the lugs 25; the 'unit heater may be suspended from' overhead structure. The heade'rs III; II' may finally be connected to the heating filiid Supply 'efihaust-pip'es 22, 23, and

- these: pipes maybe attached to either end of the headers, or a single pipe -may serve both of-the supply headers I B and another' single pipemay likewise serve both exhaust headers in series, by merely connecting the corresponding ends of each set of headers with a reverse bend and nipples in a well known manner.

When the heat transfer unit has been thus constructed, assembled and mounted, the louvers I2 should be adjusted so as to direct the warm air in the proper direction and heating fluid should be admitted to the finned coil elements 8, whereupon operation of the fan M will cause a continuous stream or current of air to be blown through the coils in contact with the radiating fins Ill. The air will thus be quickly and uniformly heated, and the warm air will pass through the spaces between the louvers l2 and will be caused to flow in the desired direction into the space which is to be heated. The rate of flow may be varied by altering the speed of the motor l6, and the direction of flow of the warm air stream may be varied by adjusting the louvers I2, while the temperature of the heated air may be varied by controlling the heating fluid supply with the aid of ordinary control valves, thus providing a unit heater which is highly flexible in use.

From the foregoing detailed description it will be apparent that my present invention provides a new and useful unit heater assemblage which is extremely simple and compact in construction, highly efiicient in operation, and which may be readily manufactured at minimum cost from available materials. By forming the heat transfer assemblage of interchangeably similar unitary elements 8 which are adapted to be reversely disposed and united as described, these elements 8 may be readily cast and dressed with minimum effort, and the use of separate outer housings or casings is eliminated. The integral construction of the finned elements 8 moreover introduces great strength and provides a compact and highly attractive unit having maximum capacity considering the space occupied. This unitary construction of the finned sections 9 and headers Ill, II also avoids the use of gaskets and joints thereby eliminating possible leakage or escape of heating medium; and the improved mounting for the flow producing fan or blower assemblage besides providing a firm support for the fan, serves the additional function of maintaining the two elements 8 firmly interconnected.

. The improved unit heaters can be manufactured and sold in various sizes at minimum cost, and may be provided either with overhead suspension means such as shown, or otherwise mounted.

It should be understood that it is not desired to limit this invention to the exact details of construction or to the Precise mode of use, herein shown and described, for various modifications within the scope of the appended claims may occur to persons skilled in the art.

I claim:

1. In combination, a pair of similar reversely assembled heat transfer elements having parallel laterally spacedheat transfer conduits and each having a side wall disposed parallel to said conduits and extending away from one of its end conduits and also having local'flanges extending in the same direction outwardly away from the opposite end portions of each of its conduits in the same direction as the said side walls, said side walls and flanges cooperating to provide an air duct directed toward the spaces between said conduits, a fan for directing air through said duct, and a fan support attached to said walls and flanges and thereby uniting said elements.

2. In combination, a pair of similar reversely assembled heat transfer elements having parallel laterally spaced heat transfer conduits and each having local flanges extending in the same direction outwardly away from the opposite end portions of each of its conduits, said flanges cooperating with each other and with the Opposite side conduits in the assemblage to provide an air duct directed toward the spaces between said conduits, a fan for directing air through said duct, and a fan casing defining a circular opening at one end of said duct within which said fan is rotatable and being secured to said flanges to rigidly unite said elements.

3. In combination, a pair of similar reversely assembled heat transfer elements each having parallel laterally spaced heat transfer conduits connected to transverse upper and lower end headers, and each also having a side wall extending away from one of its end conduits and local flanges extending in the same direction as the side wall away from each of its headers, said side walls and flanges cooperating to provide an air duct directed through the spaces between said conduits and the upper and lower headers of the two sections being disposed side by side above and below said duct in the final assemblage, a fan for producing a flow of air through said duct, and a support for said fan attached to said walls and flanges and uniting said elements.

4. In combination, a pair of interchangeably similar reversely assembled heat transfer elements each having several upright laterally spaced heat transfer conduits connected to transverse upper and lower end headers disposed on the same side of the common central plane of the conduits, and each also having a side wall extending away from one of its end conduits and local flanges extending in the same direction as the side wall away from each of its headers, said side walls and flanges cooperating to provide an air duct directed through the spaces between the two sections and the upper and lower headers of the two sections coacting with each other above and below said duct in the final assemblage, a fan for producing a flow of air through said duct, and a fan casing at one end of said duct within which said fan is rotatable and being secured to said flanges to rigidly unite said elements.

5. In combination, a pair of interchangeably similar reversely assembled heat transfer elements each having several parallel laterally spaced heat transfer conduits connected to transverse upper and lower end headers disposed on the same side of the common central plane of all of the conduits, and each also having a side wall extending away from one of its end conduits and local flanges extending in the same direction as the side wall away from each of its headers, said side walls and flanges cooperating to provide an air duct directed through the spaces between said conduits and the upper and lower headers of the two sections coacting with each other along said central plane in the final assemblage, a fan for producing a flow of air through said duct, and a support for said fan attached to said walls and flanges and uniting said elements.

WALTER J. HARTWIG. 

